Add is_debian() convenience function

rattail_fabric2/__init__.py

@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  Rattail -- Retail Software Framework
-#  Copyright © 2010-2019 Lance Edgar
+#  Copyright © 2010-2020 Lance Edgar
 #
 #  This file is part of Rattail.
 #
@@ -28,6 +28,7 @@ Fabric deployment and maintenance.
 """
 
 from .core import (
+    is_debian,
     get_debian_version,
     get_ubuntu_version,
     Deployer,

rattail_fabric2/core.py

@@ -64,6 +64,27 @@ def is_link(c, path, use_sudo=False):
     return False if result.failed else True
 
 
+def get_os_release_id(c):
+    """
+    Return the "ID" field from `/etc/os-release` file
+    """
+    contents = c.run('cat /etc/os-release').stdout.strip()
+    data = {}
+    for line in contents.split('\n'):
+        field, value = line.split('=')
+        data[field] = value
+    return data['ID']
+
+
+def is_debian(c):
+    """
+    Return boolean indicating if this machine is Debian (proper, as opposed to
+    some derivative).
+    """
+    release_id = get_os_release_id(c)
+    return release_id == 'debian'
+
+
 def get_debian_version(c):
     """
     Fetch the version of Debian running on the target system.